1. Field of the Invention
The present invention relates to a composition adapted for use in a texturing process, by which texturing streaks are formed on a magnetic disc, particularly, a composition capable of uniformly forming streaks on the surface of a magnetic disc.
2. Description of the Prior Art
In order to meet the increasing demands for higher recording densities of magnetic discs, the distance between the magnetic disc and the magnetic head must be smaller, e.g., in the order of 0.1 to 0.3 .mu.m. Therefore, it is necessary that the surface of a magnetic disc is as flat as possible. However, such a flatness of the surface of a magnetic disc is apt to cause a problem in operation, i.e., adhesion of the magnetic head to the surface of the magnetic disc (so-called as "adsorption of the magnetic head"), which either stops the rotation of the magnetic disc, or hinders the redrive of the magnetic disc after stopping, and, thus, makes starting of hard disc drive impossible. In order to prevent such an "adsorption of the magnetic disc" a so-called texturing process is applied on the ground layer of the magnetic disc (the ground layer of the magnetic layer).
The texturing process forms minute streaks on the surface of the ground layer of a magnetic disc, by scrubbing the surface of the ground layer of the magnetic disc either with a polishing tape, on which polishing grains having a predetermined grain size are cohered, or with a suspension of polishing grains. While it is necessary that the formed streaks have a certain size, in order to prevent "adsorption of the magnetic head" it is also necessary to satisfy the requirement that the streaks must not be so large as to cause the floating magnetic head to crash, and, in addition, must be formed as uniformly as possible.
In the prior art, a slurry, which is formed by mixing polishing grains of diamond or alumina in a polishing liquid, has been used as the composition adapted for use in the texturing process, in order to form such streaks on the surface of the magnetic disc.